1. Technical Field
The invention relates generally to an auger boring machine and a method of use in the trenchless installation of underground pipe. More particularly, the invention relates to such a machine which utilizes a pilot tube for forming a pilot hole for guiding smaller and larger diameter augers of the machine. Specifically, the invention relates to a swivel between the pilot tube and smaller diameter auger and a swivel between the smaller and large diameter augers.
2. Background Information
The use of an auger boring machine for installing underground pipe between two locations without digging a trench there between is broadly known. In addition, it is known to use a pilot tube formed of a plurality of pilot tube segments to create a pilot hole for guiding an auger which bores a larger hole so that the auger remains within a reasonably precise line and grade. For example, see U.S. Pat. No. 6,206,109 granted to Monier et al. An enormous amount of force is involved in driving the pilot tube and in rotating the augers. During the driving of the pilot tube, the pilot tube is rotatable to provide steering in order to keep the pilot tube on a reasonably accurate line and grade. However, once the pilot hole is completed, there is no longer a need to rotate the pilot tube and continuing such rotation substantially adds to the amount of force required in the auger boring process. Similarly, once it is time for the larger diameter auger and cutting head to begin cutting the larger diameter hole, there is no need to continue rotation of the smaller diameter auger which likewise requires additional force. The present invention solves this and other problems in the art.